The present invention relates to orthopaedic implants and, more specifically, to provisional orthopaedic implant components.
The use of implant provisionals is well known in the field of orthopaedic joint replacement surgery. Implant provisionals are often used to test the fit and alignment of an implant with a bone which has been reshaped by a surgeon. The actual implant may also be used for these purposes, however, the use of provisional components during trial fitting and alignment procedures eliminates the risk of damage to the actual implants that may be caused during these procedures.
One common type of joint replacement surgery is knee replacement surgery. For some knee replacement patients, such as those having inadequate mediolateral, anteroposterior and varus-valgus ligament functionality, it is known to use implants which partially constrain the movement of the knee joint to provide enhanced stability. Implants which provide such constrained movement may include an intercondylar box which is implanted in the distal end of the femur.
The present invention, in one embodiment thereof, provides a provisional orthopedic implant assembly which includes first and second components. The first component has a stem extending therefrom which can be adapted for insertion into an intramedullary canal. The second component has a body and a retention member slidably moveable relative to the body. The retention member is slidable between an unlocked position and a locking position. The second component can be registered with the first component when the retention member is in the unlocked position. Movement of the retention member to the locking position when the second component is in registry with the first component removably secures the second component to the first component.
In alternative embodiments of the invention, the first component is a femoral component which defines a pair of condylar surfaces and the second component is an intercondylar box. The first and second component may be secured together by engagement of the retention member with the stem of the first component. A tab and recess arrangement may also be used to register the first and second components in a desired position. The retention member is advantageously moveable by a manual process which does not require the use of tools (i.e., toolless manual manipulation).
The intercondylar box component may include a central spanning member which interconnects two parallel side walls wherein the inward facing surfaces of the side walls each have a groove and the retention member is slidably mounted in the grooves.
An advantage of the present invention is that it allows for the quick and easy assembly of a provisional device such as a femoral provisional having an intercondylar box. A femoral provisional device having a quickly and easily removable intercondylar box is advantageous in that it allows for the evaluation of the fit of the femoral provisional without an attached intercondylar box prior to cutting the bone which must be removed to allow for introduction of the intercondylar box.
Another advantage is that it provides a provisional assembly which allows for the toolless manual attachment of an intercondylar box to a femoral provisional and thereby eliminates the need to handle small separate fasteners, such as threaded fasteners, when using the provisional assembly.